Thin film metrology techniques: x-ray diffraction and x-ray reflectivity

Slight changes in doping levels can significantly affect the high-Tc superconducting properties, and x-ray diffraction (XRD) can accurately monitor such small changes in doping level at the lattice parameter scale. Thickness and interface behavior are of great significance in various device applications, such as ultra-thin Josephson junction non-superconducting interlayers and organic light-emitting diodes (OLEDs) self-assembled monolayers (SAMs). X-ray reflectivity (XRR) is becoming a widely used tool for thin film thickness measurement. Here, XRD and XRR techniques were performed on nickel-based superconductors and ultra-thin non-superconducting barrier Si layers and SAMs layers, respectively, using our proprietary instrument ÅS-D300. XRD results show that lattice parameter changes of 10^-2 Å are observed in oxides superconducting sample. In addition, thickness differences as small as angstroms in ultra-thin Si and SAMs films were successfully identified by XRR measurements.